Unveiled at an event in London on Tuesday that The INQUIRER attended, the Xperia Z Ultra essentially is a larger, improved version of the firm's Sony Xperia Z flagship smartphone, which today Sony said has been its fastest ever selling smartphone to date.

According to the firm, the Sony Xperia Z Ultra boasts the world's largest HD screen, measuring 6.4in and featuring Sony's Trilumios Brava technology, which it claims makes the screen one of the most vibrant on the market. Much like Samsung's Galaxy Note lineup, the handset also comes with stylus support, and it will also look silly when held up next to your face.

Sony also said that the Xperia Z Ultra is the world's "thinnest" HD smartphone, with the device measuring just 6.5mm thick, just slightly chunkier than Huawei's Ascend P6 smartphone. Despite being skinny, Sony claims it's just as rugged as the Xperia Z, resistant against water and dust.

Under the bonnet, the Sony Xperia Z Ultra looks to outdo its rivals with its 2.2GHz Qualcomm Snapdragon 800 CPU and LTE support, and apparently has the fastest smartphone speeds on the market. It also has Google's Android 4.2 Jelly Bean mobile operating system skinned with Sony's custom user interface, which loads the phone with apps such as Music Unlimited, Video Limited and the Playstation Store.

Although it improves on the Xperia Z in almost every area, Sony has downgraded the handset's camera, configuring the Xperia Z Ultra with an 8MP Exmor R rear-facing camera. Other specifications include a 2MP front-facing camera, 16GB of internal storage expandable via microSD card, NFC and a 3,000mAh battery.

Sony also announced its Smartwatch 2 device on Tuesday, which will be a companion to its Android smartphone lineup, ahead of its release in the UK in September.

The Sony Xperia Z Ultra will be available in the UK in the third quarter in black, white and purple flavours, although availability details have not been announced yet. µ